There is a growing national need for a system capable of detecting small amounts of radioactive material, such as special nuclear material (SNM) and shielded highly enriched uranium (HEU), especially in high traffic environments (vehicular, cargo, and human) such as portals, streets and highways, etc. Moreover, and upon detection, there is a need to identify the unknown radioactive material by its spectral signature. Various types of radiation detectors in various packages have been and are currently utilized, such as NaI, He-3, and scintillation-based field detectors, as well as cryogenically-cooled high purity germanium (HPGe) and silicon detectors. Cryogenically cooled detectors are known to require large batteries, external power, or cryogens to maintain operating temperature, and have therefore been difficult to use in the field that provides, for example, in situ diagnostics. Due to these and other problems, non-HPGe or otherwise room-temperature detectors are often used for field applications.
The low spectral resolution and performance of such non-HPGe detectors, however, have been known to make radiation source identification difficult. Additionally, many commercially available analog radiation detectors are typically configured to record spectral quality sensor data in time bins of no less than 1 second. This is often inadequate, especially for detection scenarios where a moving source is involved, and the window of detection opportunity for collecting the majority data is often a fraction of a second. For example, in a situation where a moving source passes by a detector at 65 mph with a closest approach to the detector of three meters, eighty percent of the radiation collected from the pass by will be collected in less than 0.5 seconds. For these situations involving moving radioactive sources, the use of commercially available radiation detectors with one second time binning will average out and thereby lose many features in the spectral data.
Additionally, monitoring an area for radiation often involves customizing the placement, orientation and other setup to optimize radiation detection, especially for high speed source applications known to move along a known path and/or direction. While many conventional radiation detectors record spectral data from a given localized area, there is no additional information associated with it, such as for example, the directionality of a moving source.
There is therefore a need for a radiation detections system utilizing a standard, non-HPGe detector, capable of collecting spectral data in very small time bins, e.g. less than about 150 msec, including list-mode operation of single photon detection. Such very small time bins would enable fluctuations of signal coming from the detector to be more easily scrutinized. Additionally, there is a need for such a radiation detection system to be configurable to adapt to various radiation detection scenarios, such as for example, monitoring packages, pedestrian, or high-speed vehicular traffic.